A radio access network accommodates a base station and a mobile gateway using the UMTS (Universal Mobile Telecommunications System) technology and the EV-DO (Evolution Data Only) technology referred to as 3.5G. The radio access network generally provides an IP tunnel between the base station and the mobile gateway according to the IP tunnel link technology. User data is transmitted through the IP tunnel.
Widely known technologies for providing the IP tunnel include GTP (GPRS Tunnelling Protocol) specified in 3GPP (3rd Generation Partnership Project) and PMIP (Proxy Mobile IP) specified in IETF (Internet Engineering Task Force), for example. The IP tunnel is provided between the base station and the mobile gateway or between a first mobile gateway connected to a mobile access network and a second mobile gateway included in a service network. The IP tunnel is used for mobility management of terminals.
An ordinary IP network routes IP packets in units of subnetworks to which an IP address assigned to a terminal belongs. Accordingly, the terminal cannot move out of the subnetwork without changing the IP address assigned to the terminal. An IP tunnel technology represented by Mobile IP solves this problem.
The IP tunnel technology such as Mobile IP distributes a Care of Address (CoA) to the network. The Care of Address provides an IP address that differs from the IP address assigned to the mobile terminal and indicates an IP address corresponding to the current position of the mobile terminal. The IP tunnel technology encapsulates an IP packet for communication with the mobile terminal by providing the IP packet with an IP header whose destination address stores the Care of Address. The encapsulated IP packet is transferred to the mobile terminal at the destination in order to ensure the terminal mobility.
For this reason, the IP tunnel is mainly used for mobility control over radio access networks at the present time (e.g., refer to “TS 29.274, 3GPP Evolved Packet System (EPS); Evolved General Packet Radio Service (GPRS) Tunnelling Protocol for Control plane (GTPv2-C); Stage 3” and “IETF RFC 5213: Proxy Mobile IPv6”).
On the other hand, communication speeds proceed to increase for the radio technology used for mobile terminals and base stations. The LTE/SAE system provides a communication speed of 100 Mbps. The LTE-Advanced system, expected to be a next-generation LTE/SAE radio system, will provide a communication speed over 100 Mbps.
To respond to increasing communication speeds, the radio access network (RAN) is requested to not only provide faster IP packet transfer but also apply the MPLS (Multi Protocol Labeling Switch) technology to the radio access network and replace the IP tunnel with an MPLS path. This is because the MPLS can ensure QoS for IP packets.
There is proposed a technology of replacing a Mobile IP tunnel with an MPLS tunnel (e.g., refer to Integration of Mobile IP and Multi-Protocol Label Switching ICC 2001, June 2001). Further, there is proposed a technology of providing the MPLS path from an exit node to an entry node when the mobile terminal is connected to the base station (e.g., refer to Japanese Unexamined Patent Application Publication (Translation of PCT Application) No. 2008-518532).
However, the MPLS path is installed when an LSR (Label Switch Router) between nodes maintains label switch information hop by hop. The path configuration requires updating the label switch information maintained in all LSRs to be traveled. Generally, the radio access network accommodates as many as over 1,000,000 mobile terminals. A label resource in the MPLS network might be greatly consumed and the MPLS network performance might degrade if all the mobile terminals are supplied with independent label switch paths.